L'Oréal

Same parent company, different channel and different formulation strength. Professionnel is made for salon use — that's why the shampoos come in 1500ml and the colour comes as numbered shades rather than boxed kits.

Depth before the point, tone after it. 1 is black, 10 is lightest blonde; the tone digits tell you the reflect. If you're colouring at home and unsure, the tone is the part to ask a stylist about.

Absolut Repair Molecular, ideally after the Molecular pre-treatment. Add Metal Detox if you're on hard water.

For chemically treated hair, usually yes — the concentrations and the bond-repair chemistry are genuinely different. For healthy untreated hair the gap is much smaller than the price difference suggests.

Not in this collection — it's L'Oréal hair. For makeup see Makeup, and for facial skincare Skincare.